Rocket projectile construction



March 1, 1960 E. F. CHANDLER ROCKET PROJECTILE CONSTRUCTION Filed Dec.

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INVENTOR. Edward F Chandler W flTTOR NEY United States Patent V 2,926,608 ROCKET PROJECTILE CONSTRUCTION Edward F. Chandler, Brooklyn, N.Y. Application December 2, 1953, Serial No. 395,794 Claims. (Cl. 102-49) This invention relates to improvements in rocket projectiles and the construction thereof.

An object of the invention is to provide a novel and improved rocket projectile and rocket projectile construction, which may be manufactured, loaded, stored, handled and fired in substantially the same manner as standard fixed ammunition.

Another object of the invention is to provide a rocket projectile which can be fired substantially without recoil.

A further object of the invention is to provide a rocket projectile which may be fired from a closed breech, light weight, portable gun substantially without recoil and substantially, depending upon the caliber, without flame, smoke or noise in the vicinity of the gun position.

Still another object of the invention is to provide a rocket projectile especially adapted to be dispatched from breech-loading quick-firing and/or automatic arms.

Another object of the invention is to provide a rocket projectile which will greatly increase the range, firepower and accuracy of arms adapted to be carried by the individual foot soldier, being fitted for use in such arms.

Still another object of the invention is to provide a rocket projectile in which the consumption of a large part or all of the rocket propellent powder charge is not depended upon for launching the shell, and which is adapted for use in direct fire low trajectory arms, or in mortar type arms adapted for high angle firing.

A further object of the invention is to provide a rocket projectile which is launched from a closed breech gun in such a manner that all, or substantially all of the rocket propellent powder charge is available for accelerating the flight of the rocket over its course, thereby greatly increasing the impact of the shell upon the target, as against depending upon a high initial or muzzle velocity, obtained heretofore by the rapid combustion of the rocket propellant during the launching period, in which case the energy of the launching impulse has been gradually dissipated during the flight of the shell.

Still another object of the invention is to provide a rocket projectile which upon firing, leaves the gun at a high velocity as the result of the explosion of an auxiliary powder charge within the projectile and, in such manner that a relatively small volume of gas is instantly released, when it has reached a predetermined high pressure and is therefore adapted to exert a powerful, momentary power impulse of such short duration that the energy is largely absorbed in driving the projectile from the gun substantially without recoil.

Still a further object of the invention is to provide a rocket projectile which, upon firing, is driven from the gun at a muzzle velocity sufiiciently high to be capable of setting the projectile on its course, by the instantaneous impulse resulting from the instantaneous release of a charge of gas at a predetermined high pressure and in which the release of such gas energizes the rocket propellent powder charge so that, at a predetermined point beyond the muzzle of the gun, the flight of the projectile is continued and accelerated along the course impressed upon it upon firing, by the reaction of the rocket propellent charge.

Another object of the invention is to provide a rocket projectile which is adapted to be fired in the manner described, in which the initial or launching impulse effect may be modified to meet specific firing conditions and equipment, as for example, where the projectile is to be discharged from an automatic gun and in which case energy generated upon firing the projectile may be utilized for actuating an automatic loading'and firing mechanism and for other purposes.

Still a further object of the invention is to provide a novel and improved rocket projectile in which there is a main propelling charge brought into action by a launching charge, both feeding the main jet nozzle thereof, and in which the launching charge is disposed in a launching charge chamber having a frangible wall blocking communication with the main combustion chamber and main propelling charge, the frangible wall being constructed so that it will not break until a predetermined launching charge pressure has been reached, to energize the main jet nozzle for launching, and being yet small enough in the quantity of the launching charge that there is economy of the charge while still attaining the desired objectives in use thereof;

This application is a continuation-in-part of my copending patent application, Serial Number 93,150, filed' May 13, 1949, for Rocket Projectile, now Patent 2,681,- 619 issued June 22, 1954.

The above and other objects and advantages of the invention will become apparent from the following description of a preferred embodiment thereof, as illustrated in the accompanying drawings, forming apart hereof, and in which, i

Figure 1 is a sectional elevational longitudinal view, partly broken out, showing a rocket projectile according to the invention.

Figure 2 is a left end elevational view of the rocketprojectile shown in Figure 1. p

Figure 3 is a sectional elevational view taken substantially on plane 33 of Figure 1. V

Figure 4 is a fragmentary sectional plan view taken substantially on plane 44 of Figure 1, and showing one of the spider struts thereof. Figure 5 is a fragmentary longitudinal sectional elevational view showing a modified form of the invention, in which the construction is generally similar to that of Figure 1, one of the main differences being that the percussion cap is located at the rear of the projectile, the firing rod being eliminated, and there is a delay charge intermediate the percussion cap and the launching charge.

Rocket propulsion of projectiles carrying high explosives for ordnance purposes and the use of rockets for other purposes is now well established. Modern warfare has made increased and insistent demands for use at the immediate front line of combat encounter of larger caliher and heavier projectiles than can be fired from prior art weapons with which the individual foot soldier can be armed, or which may be fired from light structure moblie guns.

The increased use of artillery, for the satisfaction of this demand, is prohibited by its initial impedance and unsuitability for advance by portage, and by the mass of carrage, barrel and mechanism being too great for light weight, highly mobile equipment. The field equipment now required by armies must be light, fast, and extremely mobile and in present military tactics, speed and mobility are of ever increasing importance, such as to subordinate factors of economy previously considered to be dominating, and which were thought to exclude consideration of rocket propulsion for projectiles.

Accordingly, rocket projectiles, because they may be fired from a light weight tube or trough, have found an. important place in modern military and naval operations. The weight of the ammunition is comparable with that used by artillery pieces but the means for launching the same is extremely light and highly mobile. As is well known, a rocket projectile fired from an'open tube ortrough produces no recoil. However, the rearward discharge from the rocket motor, upon firing, has been a Patented Mar. 1, 19 0 l A 3 serious limiting factor militating against the application of rocket propulsion to a number of important uses.

The rearward flame-blast is dangerous to personnel, since it presents a serious fire hazard for a considerable area behind the launcher position, and it also discloses to an enemy the position of the rocket launcher. The seriousness of these objectionable features becomes more obvious and of greater tactical importance as the rocket arm is carried closer to the area of combat encounter.

Also, the back-fire from the rocket motor has precluded its use in light guns mounted in turrets or other confined spaces. It has been proposed to fire rocket projectiles from a closed breech, smooth bore gun, the gun muzzle being equipped with some form of brake, in an effort to reduce the recoil effect resulting from the high power blast of the motor upon launching. Also, a booster charge has been proposed, but, like other methods pro posed, has not come into general use, and rockets are still being launched in substantially the same manner as was employed in the early days of the art.

Numerous improvements have been made in the various elements constituting the modern rocket motor, but little progress has been made in the development of a system in which full advantage has been taken of the important features of the rocket motor as it is known today, plus means which brings it into direct line as an important factor in a substantially new type of arm. The present invention provides such means.

This invention is also a continuing application of the inventions disclosed in copending patent applications of the present inventor, which have matured into patents as follows: Serial No. 545,585, filed July 19, 1944, for Rocket Projectile, Patent No. 2,500,117 datedMarch 7, 1950; Serial No. 607,613, filed July 28, 1945, for Rocket Projectile, Patent No. 2,524,591, dated October 3, .1950; Serial No. 416,442, filed October 25, 1941, for Projectile and Method of Shell Propulsion, Patent No. 2,504,648, dated April 18, 1950; and of copending patent application, Serial No. 93,150, filed May 13, 1949, for Rocket Projectile, Patent No. 2,681,619, dated June 22, 1954.

In order to understand clearly the nature of the invention, and the best means for carrying it out, reference may now be had to the drawings, in which like numerals denote similar parts throughout the several views.

As seen in the drawings, there is a projectile including a rocket motor body 68 with a chamber 71 formed therein and containing a main propellent charge 70 disposed in the chamber, but incompletely filling the same. There is thus formed the combustion chamber 81 upon which the rearward portion of the charge 70 opens or faces. The rocket motor body is rearwardly convergent as at 72 to form a constriction at 83, and thereafter rearwardly divergent as at 79 to form the nozzle discharge opening at 77a, thus defining the main jet thrust nozzle passageway 78.

Stabilizing fins 76 are carried on the outside of the nozzle portion of the rocket motor body, radiating therefrom, and being held in position by any suitable means, such as a ring 74 secured thereto, the fins also being secured to the outside of the nozzle as at 79, by welding or other means. In the reaction zone 81 and secured therein in any suitable manner, is a spider 80 having an extended portion 82 within which is a chamber 99 containing an explosive powder charge 98. The forward end, or rightward end, as seen in Figure l, of the charge chamber 99 is sealed by a frangible disc or wall member 100 clamped in place by a threaded ring 104 having a passage 102 formed therethrough. At the rear of the chamber 99 is a percussion cap 86 or other suitable detonating means communicating with chamber 99 by flash duct 84, the percussion cap 86 being retained in position by the threaded reduced perforated portion at the rightward end of the guide tube or member 88.

The guide tube or member 88 has an axial bore 77b in which is disposed the firing rod 90 carrying the firing pin 91 for movement therewith, at its rightward end, the

firing rod being retained against accidental operation by. any suitable means such as the shear pin 92, and also the rearward end 94 of the rod is set-in, so contact with the rearward end of the tail by some outside surface will not disturb the rod. When the detonating means 86 is actuated, the action produces a burst or flame which is communicated through opening 84 to the charge 98 in chamber 99, and when a predetermined pressure is reached within the chamber 99, the disc 100 is burst, and the high pressure gases flow through passage 102 into the reaction zone area 71 and 81, and out through the nozzle 78, to energize the nozzle, and launch the projectile. At the same time, the main propellent charge 70 is ignited, the combustion thereof taking up and continuing the ener-. gization of the nozzle 78, to continue and accelerate the flight of the weapon.

The powder 98, burning in its confined space under pressure, is thus completely consumed, generating sufficient gas pressure to burst disc 100, and the hot high pressure gases thus release a sudden burst of high pres-. sure for actuating the jet nozzle 78 to produce rearward thrust for launching. At the same time, these hot, high pressure gases from the charge 98 also serve to ignite the rearward or leftward surface of the main propelling charge 70. This rearward surface of charge 70 may be coated with a layer of quick-burning ignition powder for insuring the start of combustion of the propelling charge 70. The rocket propellent charges 98 and 70 may be of any suitable rocket powder composition, and may be molded if desired to fit their respective chambers. Also, the main rocket propellent charge 70 may be molded in the form of hollow annulus or cylinder, with a center core of less densely packed powder of the same or different type, to insure uniform surface burning for even generation of gas pressure. Further, the leftward end of the main charge 70 may be covered with a delay action powder, so that ignition of the main propellent charge 70 will not take place until a predetermined time interval has passed.

It is thus observed that the cap 86 is first actuated by means of the firing pin or other means, actuating the charge 98, bursting the disc 100 and allowing the launching gases from charge 98 to enter the combustion chamber 81, and to leave rearwardly through the nozzle 78, launching the projectile. Because of the substantial absence of recoil, it is believed the above actuation of nozzle 78, which serves to produce sufiicient velocity drive to launch the projectile may be a reaction eifect in which some of the energy is absorbed by the projectile. and gun parts, the rapidly traveling shock-wave, which is believed to occur, impinging upon an internal portion of the forwardly moving projectile, to drive the same while some of the energy of the small volume of rapidly expanding gas from charge 98 is dissipated in the progressively expanding or increasing space within the barrel, between the butt of the projectile and the inner face of the breech block of the gun.

In the method described herein, the relatively small volume of gas generated by the charge 98 is suddenly released at maximum pressure starting the launching movement of the missile without delay and almost instantly expands to atmospheric pressure, whereas, usually in launching a projectile the relatively larger quantity of powder necessary, upon combustion within the gun breech, first builds up to and develops a very high pressure and then this pressure is reduced as the gas expands during the forward movement of the projectile in the.

ly, the gas evolved from the explosion of the relatively larger quantity of powder necessary to develop the'desired' muzzle velocity, expands beyond the gun muzzle with a release of flame and smoke, and the noise of the explosion.

As seen in Figure 1, the forward end of the rocket motor body is threaded at 110 onto the rearward end 114 of the shell body or warhead 118, which is reduced and threaded as at 112, with a heat insulating disc 116 disposed between the rearward wall 119 of the shell body and the forward end of the rocket main propellant 70. This is not essential in short range missiles ordinarily, but in long range missiles the heat generated by the rocket propellant might afiect the bursting charge 120 disposed in the body 118 ahead of time, instead of by means of the fuse 122 in the desired manner on reaching the target. The fuse 122 may be threaded into the forward portion of the shell body 118 and may be of any suitable impact or time delay type, and provided with a suitable booster charge adapted to actuate the bursting charge 120 upon reaching the target.

For the purpose of checking the principle underlying this invention, experiments were made with a projectile one and one-quarter inches in diameter, weight being one and one-fifth pounds, in which the auxiliary disc bursting powder charge occupied a space A inch in diameter by A inch long, and weighed 0.0017 pound, or about of the total weight of the projectile, loaded, ready for firing. The projectile was fired horizontally, from an 18 inch long, light steel tube having a closed breech equipped with a firing pin and hammer. The object was to demonstrate that it is possible, upon pulling the firing latch, to instantly discharge the projectile from the gun a safe distance before full rocket action takes over, the target being positioned 35 feet from the gun muzzle.

In repeated tests, the projectile was dispatched against the target at high velocity, noiselessly and without the presence of flame or smoke. The operation resembles dispatching a projectile by means of compressed air. The absence of any substantial recoil is important and an interesting feature of the system. For comparison, the same projectile was fired from the same equipment, employing in this instance a relatively heavier powder charge than was normally heretofore required to dispatch a projectile weighing a pound and one-fifth at the previously attained muzzle velocity. When thus fired, the recoil wrecked the light test stand previously used, and there was considerable smoke-haze and flame from the gun muzzle, accompanied by a loud report.

It has not yet been fully determined whether the ratio between the weight of the disc-bursting powder charge and the total weight of the loaded projectile of approximately 1:700, which has been reasonably well established for projectiles of 1.25 to 2.00 inch calibers, will hold for all caliber ranges. It appears obvious however, from the work that has so far been done that, by the method disclosed, rocket projectiles of various calibers can be fired at relatively high muzzle velocities, from closed breech guns in substantially the same manner as fixed ammunition is now fired, with little or practically no recoil and the absence of objectionable smoke, flame and noise to betray the gun position.

It is necessary only that the initial firing action carry the projectile far enough ahead of the gun muzzle to protect the gunner from the nozzle discharge of the rocket motor of the projectile and, depending on the caliber, this distance may be of the order of five feet for a rocket fired from a shoulder gun to 30 to 100 feet or more for larger calibers. A purpose is, as previously pointed out, to start the projectile on its course immediately the arm is fired, as in artillery firing, and at a sufficient velocity so that the rocket propellant becomes fully energized in time to continue the flight of the projectile on its predetermined course and to accelerate the speed of the projectile over all or a substantial portion of its trajectory.

It has become the practice, in order to quickly dispatch a rocket from a launching tube, to employ a type of rocket propellent powder which burns at a rapid rate with the result that most, if not all, of the powder is consumed in launching the projectile. Accordingly, in such case, the speed of travel and the range of the projectile depends almost entirely upon the energy impressed upon it initially and not upon the continued drive of the rocket motor jet. According to the present invention, it is possible to employ a slower burning propellent powder'and thereby maintain a substantially constant pressure on the rocket motor power jet throughout a greater portion of the flight, thereby increasing the range, and, due to the accelerated velocity causing the projectile to strike its target with greater force. I

This is made possible by the firing method described herein which does not depend upon immediately energizing the rocket propellent means for starting the projectile on its course, that is the main propellant such as 70.

This is a feature which adapts projectiles constructed in accordance with the invention, to use as ammunition for various types of light, highly mobile, quick-firing and automatic arms. Rockets have been fired from mechanically operated and mechanically automatic feeding demechanism as in so called gas-operated systems vices. What is referred to herein, however, pertains to automatic arms which depend for their operation upon energy derived from the firing of the ammunition, which may be utilized for loading, firing and/or cocking the and the like employing standard fixed ammunition.

The explosion of the small powder charge 98, employed for bursting the frangible disc 100, as used in the 1% inch caliber projectile, instantly releases a pressure of approximately 38,000 pounds per square inch, and it has been found among other modifications that by increasing or decreasing the volume of the initial reaction space 71, in Figure 1, more or less of this energy can be made available for actuating the operating mechanism of an automatic loading or firing arm. This powder exploded under high. pressure is totally consumed so that the gas discharge is clean and better suited to the operation of such mechanism than the gas discharge from the usual machine gun cartridge and less likely to foul the barrel and moving parts.

This is beacuse the gas, in the former instance, is generated and expanded under a diminishing pressure condition, with an evolution of incompletely burned products of combustion. It will also be understood that the pressure released upon the bursting of the frangible disc 100, which maybe of suitable metal or composition materials or alloys, which will rupture at the selected pressure, may be increased or decreased by changing the thickness of the disc or otherwise modifying its resistance to rupture and/ or by adjusting the effectiveness of the powder charge,- in any suitable manner to meet a predetermined operating condition. A rocket projectile of the order herein disclosed, while designed to adapt rocket type ammunition to closed-breech guns, breech-loading arms, and the like, may also be fired from a tube or trough in the usual manner. Certain advantages may thus be realized, among which is reduced fire hazard during launching.

Other tests were made at a later time than those mentioned in column 5 herein, under closer check conditions,- and show further and improved results. Thus a projectile was employed which is of a diameter of one and one-fourth inches outside, and eight inches long, Weight being one and one-half pounds total. In this test, the launching powder charge weighed five grains, the copper bursting'orfrangible disc being inch thick. When discharged from a smooth bore gun eighteen inches long, with the breech closed, the projectile travelled at a muzzle velocity sufficient to drive the projectile a distance of 200 feet, under the influence of the launching charge only. It is thus apparent that here the weight ratio between the launching powder charge and that of the projectile is one to twenty-one hundred. The range of 200 feet attained was with the gun set at an eight degree elevation angle, indicating a substantially fiat trajectory. While an initial range of about 200 feet is shown, it will be understood that it would be safe to have the rocket main propelling charge take over about ten to fifteen feet forward of the gun muzzle, the greater distance obtainable showing that there is sufficient velocity so that directional accuracy will be maintained, the rocket power acting to accelerate the speed along the original aimed course.

Referring now to Figure 5, it is seen that it shows a longitudinal sectional elevational view similar to that of Figure 1, except that it is a modified form of construction. In this form of the invention, those parts which are numbered similarly to Figure 1 are similar thereto. However, it is seen that the firing rod 90 of Figure l is omitted, and the percussion cap 86a is located at the rearward portion of the axial housing extension 88a. A flash hole is seen at 84a to carry the blast of ignition of the cap 86a to the delay powder charge 130 which is disposed in the extension 88a which is axial through the nozzle 78, and is located in the axial bore 132 in housing 88a. The launching charge 98a is disposed in bore 99a as in Figure 1, and the frangible wall 130 blocks egress of the resulting gases until sufficient pressure has been built up, as explained hereinbefore. The cap 86a may be actuated by being struck by the firing pin of the gun in which the projectile is to be launched, or in any other suitable manner.

Although I have described my invention in specific terms, it will be understood that I do not wish to be limited to the specific examples and embodiments disclosed, and that other sizes, shapes, dimensions, and materials, varying from those shown, may be employed without departing from the spirit and scope of the inven tion as claimed.

I claim:

1. A projectile comprising a projectile body having a first chamber formed therein, a main rocket propellent charge disposed in the forward portion of said chamber, with a combustion chamber forming a portion of said first chamber rearwardly of said main rocket propellent charge, the rearward portion of said projectile body forming a nozzle for propelling the same upon receiving gases from said combustion chamber, a spider disposed in said combustion chamber, a launching charge carried in said spider, means for actuating said launching charge to produce high pressure gas, frangible wall means disposed intermediate said launching charge and said combustion chamber and adapted to resist breaking until a predetermined launching gas pressure has been reached, whereupon said launching gas enters said combustion chamber and is discharged by said nozzle to produce initial launching of said projectile, said launching gas being adapted at the same time to effect initiation of the actuation of said main rocket propellent charge, whereby, after said launching of said projectile, said main charge produces propelling gas sufiicient to continue and accelerate the flight of said projectile.

2. The construction according to claim 1, wherein a plurality of stabilizing fins is carried by said projectile body and wherein a firing rod is carried by said spider, a firing pin on the inner end of said firing rod and adapted to actuate said means for actuating said launching charge, the outer end of said firing rod being disposed wholly inside the outlines of said projectile, whereby accidental actuation thereof is avoided.

3. A projectile comprising a projectile body, a wall in said projectile body and defining a first chamber therein, said wall constructed so as to smoothly converge rear wardly to form a constricted throat and then expanding rearwardly of said constricted throat to form ,a thrust nozzle opening communicating from the outside of said projectile body to the interior of said first chamber, an

elongated housing extending through said thrust nozzle and throat and spaced from the walls of said nozzle and throat thereof to define an annular passageway outside said elongated housing for the passage of gases for propelling said projectile, a recess formed in said elongated housing to define a launching charge chamber, a launching charge disposed in said launching charge chamber, said recess opening upon said first chamber, frangible wall means disposed intermediate said recess and said first chamber to normally block communication therebetween, and constructed and arranged so that said wall means will resist breaking until a predetermined launching gas pressure is attained in said recess upon ignition of said launching charge, and adapted thereupon to break said frangible wall means and enter said first chamber, flowing rearwardly through said annular nozzle passageway to provide reactive thrust for launching said projectile, means for actuating said launching charge, and a main propelling charge disposed in said first chamber and incompletely filling the same, and constructed and arranged for being actuated at a predetermined time following actuation of said launching charge, for propelling said projectile in flight.

4. The constructitn according to claim 3, characterized further in that there is a frontal portion of said projectile carried on a forward portion of said projectile body, and constructed and arranged for carrying a useful load.

5. The construction according to claim 3, characterized further in that there is a frontal portion of said projectile carried on a forward portion of said projectile body, and defining a head chamber, a bursting charge disposed in said head chamber, and fuse means constructed and arranged for actuating said bursting charge at a predetermined time interval or upon reaching a target, for bursting said head chamber.

6. The construction according to claim 3, wherein there is a spider disposed in said first chamber and formed with spider legs radiating outwardly to and secured to the inner surfaces of the wall of said first chamber, said spider being secured to said elongated housing for supporting the same in spaced relation to the walls of said first chamber and said nozzle and throat.

7. The construction according to claim 3, wherein said launching charge chamber opens upon the portion of said first chamber which contains said main propelling charge, whereby, upon rupture .of said frangible wall means, the force and heat of said actuated launching charge is directed against said main propelling charge, and wherein said main propelling charge is constructed and arranged for being actuated thereby.

8., The construction according to claim 3, wherein said launching charge is of minimal quantity just sufiicient to achieve said launching function before being entirely consumed, whereby the same may be launched from a closed breech gun, with substantially no smoke, flame or noise upon launching.

9. A projectile according to claim 3, wherein the weight ratio between said launching powder charge and that of said projectile is one to twenty-one hundred, substantially.

10. A projectile according to claim 3, wherein said projectile weighs one and one half pounds, and wherein said launching powder charge weighs five grains, and wherein said frangible wall means comprises a copper disc which is 5 inch thick.

References Cited in the file of this patent UNITED STATES PATENTS 1,994,490 Skinner Mar. 19, 1935 2,462,135 Skinner Feb. 22, 1949 2,627,160 MacDonald Feb. 3, 1953 FOREIGN PATENTS 379,654 Italy Apr. 2, 1940 

